Resistance welding of sheet metal coated with layers

ABSTRACT

The invention relates to a method for the resistance welding of sheet metal coated with layers, wherein firstly electrical contact is established between the sheets to be interwelded and between the welding electrodes and said sheets, and subsequently welding is effected across the coating layers. The invention relates also to machines for carrying out this method.

1 1 Dec. 11, 1973 United States Patent 1191 Becker Williams et al.

c a n. M C m ,lflu UAm SPC 6802 6439 9998 11.1.1 0119 ll Primary Examiner-J. V. Truhe [22] Filed: 1970 Assistant Examiner-Hugh D. Jaeger 21 AttorneyGeorge R. Douglas, Jr.

App]. No.: 102,951

Related US. Application Data [62] Division of Ser. No. 704,684, Feb. 12, 1968, Pat. No.

ABSTRACT The invention relates to a method for the resistance welding of sheet metal coated with layers, wherein firstly electrical contact is established between the sheets to be interwelded and between the welding electrodes and said sheets, and subsequently welding [52] US 219/91, 219/92 [51] Int. B23k 11/10 [58] Field of Search.............. 219/91, 92, 137,

is effected across the coating layers. The invention relates also to machines for carrying out this method.

S T N m MA :IP m mT ms e D RE H N U 6 U 3,337,711 8/1967 Garscia................................. 219/92 3 Claims, 51 Drawing Figures Pmgmgnnac 11 ms 3,778,583

' sum 01 or :5

Fign

minimum: n ma SHEET OEOF 25 SHEET OHUF 25 PATFIHEUHEC 17 m5 3.778.563 sum 050$ 25 PATENTEU DEC 1 I 1975 m n m sac 1 2 am 3.778.583 SHEET USBF 25 sum 12 0F 25 PATEHTED cal 778,583

FATENTEDEEBH 197a 3778583 SHEET 13UF 25 PATENTEDBEC 11 I575 SHEET 170F 25 Fig.

1 Fig.39 

1. A method for resistance welding of insulation-coated sheet metal to at least one other coated sheet metal, said method comprising arranging on the superposed sheet metals a pair of juxtapositioned main electrodes and, side by side thereto at least one pair of juxtapositioned auxiliary electrodes, each of said auxiliary electrodes being electrically insulated from each main electrode arranged at the same side of the sheet metals to be welded, and being connected to the main electrode arranged at the other side of the sheet metals by shunt lines, passing current from the main electrode on one side of the sheet metals to be welded through the metal sheet in contact with said main electrode to the auxiliary electrodes on the same side of the sheet metals, so as to heat said metal sheet and to melt the coating layers on subsequent welding, establishing contact through the shunts from said auxiliary electrodes to the main electrode on the opposed side of the metal sheets, and subsequently welding the sheet metals simultaneously through the juxtapositioned main electrodes and auxiliary electrodes.
 2. The method of claim 1, in which the pairs of juxtapositioned auxiliary electrodes are constructed as welding tongs and in which shunts are provided leading from the upper main electrode to the lower auxiliary electrodes of the welding tongs and from the lower main electrode to the upper auxiliary electrodes of the welding tongs.
 3. A method for resistance welding of insulation-coated sheet metal to at least one other sheet metal comprising arranging on top of the sheet metals to be welded a first welding appliance with a spatially parallel positioned first main electrode and a first auxiliary electrode electrically insulated from said main electrode and beneath the sheet metals to be welded a second welding appliance with a spatially parallel positioned second main electrode and a second auxiliary electrode insulated from said second main electrode, the main electrodes and the auxiliary electrodes being in juxtaposition to each other, providing the outermost sheet metals on its coating layers with stripped zones on the spots to be welded, connecting the first auxiliary electrode of the first welding appliance by a shunt with the second auxiliary electrode of the second welding appliance, passing current from the first main electrode through the upper sheet metal to the spatially parallel positioned first auxiliary electrode and from there through the shunt to the second auxiliary electrode of the second welding appliance through the lower sheet metal to the spatially parallel positioned second main electrode to cause heating of the metal sheets and melting of the coating layers, and subsequently welding the sheet metals simultaneously through the juxtapositioned main and auxiliary electrodes. 